In conventional spinning and twisting operations, a plurality of spindles are arranged in a row on a frame beneath a vertically reciprocated rail. The rail supports a plurality of twister or traveler rings, one for each spindle, with the rings being arranged to be reciprocated with the rail along the length of the spindle associated with the particular ring. A small, lightweight traveler or guide is arranged to freely move about the ring. The traveler rotates about the spindle so that a body of fibers, filaments, yarn, or the like may be engaged by the traveler as the fibers are fed from drafting rolls and are wound on a bobbin supported on the twisting spindle. The travelers generally have an intermediate portion and horns defining a gap therebetween for slidable mounting on a flange of the spinning ring.
The limiting factor with respect to increased spinning speeds is the wear force between the traveler and the ring. As the textile industry moves to higher spinning speeds, traveler speeds also increase. As spinning speeds increase, both tension, which is the force exerted by the yarn on the traveler, and friction, which is the force that opposes relative motion between the yarn and the traveler and between the traveler and the ring, increase.
Collateral to the problems of wear resistance are those of lubricity. As the polished surfaces of the traveler wear down, they become roughened and increase the coefficient of friction between the traveler and the ring, resulting in increased friction and potential heat build-up. It is not uncommon for the horns of travelers to burn off which, in addition to loss of production time for replacement of the traveler, can cause damage to the yarn and the ring.
In addition to heat build-up, a roughened traveler will fray and eventually break the yarn, causing lost production time and a low quality end product. Such roughened travelers tend to become loaded with excess fibers which cause the travelers to require cleaning or replacement.
Conventional travelers are generally made of hardened steel wire and, of course, contain iron. Travelers are usually finished with a variety of coatings including nickel plates, oxidation finishes, ceramics, and teflon composites. Each of the coatings attempts to solve problems of corrosion resistance or wear resistance. The present finishes, however, are insufficient to resolve all the problems associated with the wear of travelers and rings used in high speed spinning operations.
For example, nickel platings often cause a transfer of material to the ring which, in turn, results in accelerated traveler wear after the nickel plating is initially penetrated. Oxidation finishes cause a softening or tempering of the hardened steel during application thereof. Ceramic finishes also soften the steel surfaces, allowing for severe wear on conventional rings. Teflon composites, while offering various advantageous, can exhibit problems similar to those associated with nickel plated coatings in that they tend to wear off quickly, leaving bear surfaces subject to additional wear.
During the initial break-in process of conforming the traveler to the ring surface, a minor amount of traveler material must be removed. Such seating action is necessary for heat conduction and lowering of contact stress. Wear of the ring and/or traveler is accelerated if removal of this material damages the ring surface or deposits abrasive materials thereon.
To decrease wear and friction, various oil-based lubricants such as those described in U.S. Pat. No. 3,304,710 to Kluttz have been employed for lubricating the ring in traveler assemblies. Moreover, various electroless plating methods such as those discussed in U.S. Pat. No. 3,226,924 to Dalpiaz have also been utilized to apply various coatings to travelers and rings.
An alternative approach to the problems of lubricity and wear has been to provide polymeric, rather than metallic, rings and travelers that inherently allow for a lower coefficient of friction. Plastic travelers have the added advantage of being lightweight. Such lightweight travelers have not yet proven themselves in high speed spinning operations.
Plastic parts, however, are poor conductors of heat and have relatively low softening points. In the case of metal rings and travelers, friction therebetween develops heat which is rapidly conducted away from the traveler. Because of the poor conductibility of plastic, heat poses a major problem to plastic parts. U.S. Pat. No. 3,387,447 to, Trammell et al. addresses this problem by adding particles of conducting material such as bronze, copper or graphite to the plastic rings. However, it is generally known that such plastic parts, particularly plastic travelers, are only suitable for use with the heaviest yarns.
Although various coatings and lubricants for rings and travelers are known, the particular features of the present invention are absent from the art. The prior art is generally deficient in affording a high wear, low friction coating that may be applied to rings and travelers. The present invention overcomes the shortcomings of the prior art in that the coating composition disclosed herein results in travelers and rings having sufficient wear resistance for high speed spinning applications while at the same time providing low friction surfaces.